They said no such thing.
 

HazelNuts39's post (#30), after which even a PPL would understand the impossibility of what the rewriting of BEA's words is claiming, should have laid this one to rest.

Parsing and out of thin air indeed.

Hi PJ2,

There was a post, #2062 by SaturnV on the R&N AF447 thread regarding the deviation ("Can you maybe go to the left?"). He posted a satellite weather overlay where this turn to the northwest occurred that was posted earlier by MM43. If this is at all somewhat accurate, it would appear they recognized the weather ahead (perhaps a little late) and were using their radar to shoot the gap between two CB's, the one on the right being slightly more significant than the one on the left. And as they did so, the turbulence increased and they reduced speed to MACH .80. They probably had no time to ask for a deviation at this point in time and it wouldn't appear they needed to deviate for very long.

Just some thoughts.

Hello Turbine D;
Entirely plausible, TD - Absence of communications for an ATC clearance to deviate for weather does have other explanations. As I mentioned, I've had to do it just once - SFO HF was terrible, (noisy and crowded), there was no such thing as "CPDLC" and we HAD to start the turn in the next ten miles. Rare, but it happens. Normally it's accompanied by a broadcast in-the-blind on 123.45 and possibly 121.5 but maybe it got really rough quickly - the need to bring back the Mach doesn't occur very often. The pitch-up may have a similar, plausible explanation, before it got out of hand, that turns out to be entirely different than what has been posited thus far. We'll know soon enough I hope.

Wow.
 

I'm disappointed I didn't get any response from pilots to my last question, but that isn't going to hold me back from saying I think some of you (Bearfoil) are appearing to be frighteningly closed to the notion that the airplane may well have been just fine, but the PF screwed the pooch.

Good grief man, from what we "know" so far, it's the most logical solution to all questions.

Now, why he might have done so leaves all sorts of questions to answer, but all of this mind numbingly tedious examination and re-examination of every nitty gritty detail of the aircraft and suppositions of failures can surely wait until the rest of the data is shown to us all?

Are we?http://images.ibsrv.net/ibsrv/res/sr...lies/smile.gif

Yes it does.

You seem to feel very strongly about "not following a procedure/rule" being a reason of not being an "intentional" climb.

Yours, and the reason posted by Lonewoolf - no additional throttle during the climb - and above all - perhaps not a surprise to you - the energy conservation calculation showing that the kinetic energy at FL350 and FL375, based on the BEA text are matching the climb potential energy, showing that no additional power was applied, are convincing.

With the risk of repeating what was perhaps already said, the implication of the calculation results is that while it shows that no additional power/throttle was applied during the climb, it also shows that no additional energy came from outside the A/C, like from the air turbulence providing additional lift.

However, what the calculation cannot show, is weather the air turbulence had a downward gradient, adding a downward force to the A/C weight, and thus delaying the A/C pitch-up response to the NU command, in spite of the correct response of the control surfaces.

The effect of this can be that the PF entered a gradually more forceful NU command, proportional with the delay of the A/C response, which resulted at the time of the change of air turbulence gradient into a sudden, much more aggressive pitch than intended, and a more aggressive climb at 7000ft/min.

A factor of surprise for such a sudden response may have been the cause of the delay to the ND command, slowing the climbing vertical speed from 7000ft/min to 700ft/min.

Yes I do, and there is one simple reason: an airline pilot lives by SOPs and "flies by the book." There are no "individual actions" anymore, in the cockpit of a transport aircraft. Cockpit discipline and crew coordination and communication in normal and abnormal circumstances is what keeps everyone safe when something bad happens. Remove that and the flight is at risk. It is no more complicated than that.

I am aware that there may be "energy for the climb without pushing the thrust levers up a bit", but that misses the point entirely. No matter how it was done, any pitch-up at all is absolutely the wrong thing to have happen and the expectation is that it would be resisted with all necessary force on the stick to maintain level flight with the thrust unchanged.
Sorry airtren, I may be mis-reading your post but according to these paragraphs it appears that you believe that the pitch up itself was a necessary manoeuvre, and I cannot think of a single good reason why aft sidestick would be applied within seconds of the autopilot and autothrust disconnect. Assuming the event occurred in stable, level flight, it is unquestioningly the wrong response to a loss of airspeed information and a disconnection of the autopilot.

And while it is quite possible that the BEA Update did not include all communications between the PF and the PNF on a timeline, it appears to me that this pitch-up action took place unilaterally, without the PF announcing what he was doing, what the drill to be actioned was, an what the PNF was to do.

I am of the view, supported by the BEA Update that the aircraft was pitched up past 10 degrees attitude at FL350 and kept there with aft sidestick, instead of pushing the stick full forward and keeping it there as is the SOP for stall recovery.

Perhaps, as I have said, there are other reasons for the pitch up which were initially unintentional and beyond the immediate control of the PF. However, the BEA Update makes it clear that sidestick input was aft with a few momentary exceptions, commanding up elevator, from which the THS slowly followed up upon, as it was designed to do and the stick was held back during the approach to the stall and in the stall.

I think it is this initial pitch-up, and then the aft sidestick position at the entry into the stall and held during the stalled descent, with a momentary relaxation, that needs to be explained.

Attitude faults
 

As far as I can remember, this was all about the optional BUSS (Back Up Speed System) not installed on AF fleet. Hence, this is not related to inertial references or standby gauges. In this regard, AF opted for optional ISIS as a backup instrument display.

Actually, the BEA report #2 explicitly ruled out attitude failure:
Fact/findings: None of the messages present in the CFR indicate loss of displays or inertial information (attitudes)
This fact was not challenged by further findings, including CVR and DFDR readings. What the BEA is stating in the last note as being the current pitch angle, at certain time, is comming directly from the same source used by the pilots. Even if ADIRU 2 (F/O's source) is not recorded, the way the system monitors the attitude sources (IR references) is ruling out that it could be at any time in error with the other sources recorded (ADIRU 1 & 3).

The BEA reports, as well as the fault sequence analysis, is showing that no attitude degradation of the PFD and ISIS ever occured during this flight.
PFD and ISIS are displaying a lot of informations, each linked with various functions. The faulty functions recorded in the ACARS CFRs (current flight report) is showing faults unrelated with aircraft attitude.
- ISIS failure: what faulted was the Speed/Mach function; specifically (now with further avail. data), it is showing that static pressure was at one point higher than total pressure (pitot/static probe 3 related fault); this happened between 0211:00 and 0211:59 (at this point, aircraft had already reached its top climb, 38,000 ft, and was certainly stalling).
- ADRIRs failure: the one reported by IR parts of the 3 ADIRUS is also related to probe issues: it is pointing that either values of pressure altitude, barometric vertical speed and true airspeed were invalid on the three ADRs (possibly all three cited values were wrong). As above, this happened between 0211:00 and 0211:59, same remarks.

Beside, Quantas issues with a faulty ADIRU was also unrelated to IR faults.

Right, but basic speculations should be based on the whole dataset, not discarding a single information or pushing wilde interpretations of automatized systems which are basically highly predictibles (because they have been built to behave like that, this is a very deterministic process, unlike crew actions).

When one reads many other reports (in whatever context) about human behavior in stressful circumstances, this is not very hard to catch up that a wrong initial analysis may surely lead one to sustained wrong acts. Here "the Crew" is a too strong term as for explaining the first sequence until reaching max altitude. This lasted no more than 40-50 seconds, Captain was in his bunk and PNF was certainly very busy with systems checks rather than monitoring exactly what the PF was actually doing, not even talking about him making some cool headed instrument scans.

Really?

A simple conservation of energy calculation would show that a 3000ft climb requires a loss of 260 Knots of true airspeed.

gH = 1/2 x (V^2) where V is the speed change and H is the height change
So in metric units V=SQRT(2 x 9.8 x 914)
V=133 metres per second (approx 260 Knots decrease)

And that assumes a 100% efficient energy transfer - not usually provided by an aerofoil heading deep into the back of the drag curve.

So I would not be so sure that there was not a significant input of lift from the surrounding environment.

TAKATA #565

So for a few seconds PNF was busy - doing what ever was necessary.
And PF was flying by SS, using those instruments without warning flags etc.
No one had the spare ability to scan, for this short time, or to notice that the THS ( which we never touch - we let it do its own thing...) has trimmed in only one direction, not cycling as usual -- a little NU followed by a little ND.

So PF was busy, too.

Dont Hang Up -
 

I think we have been around this one before. Hazlenuts39 has made a detailed analysis of airspeed in one of the previous threads.

I am mere SLF, but my maths says that kinetic energy would be based on TAS (kinetic energy does not know, or need to know, about air density).
A quick calculation on this basis would have the resulting speeds drop by about 20% for a ~900m climb - or about 260 knots (IAS) down to about 210. I believe this is consistent with the BEA report at the point that speeds returned?

@Bear:
 

Not as advertised, it is kept stowed by hydraulic lock internally.
Of course after degradation internal leakage could be introduced but this
was youngest A330 in AF fleet (MSN 660 age:4years 3 months).
It's position remains monitored even if locked by FCPC/FCSC command.


In AP mode rudder trim is deactivated. as last step after Eng. startup any rudder trim should be zeroed.


– RUD TRIM ............................................................ ............................................................ ......ZERO

Understand me well.
a) I'm addressing here the initial climb (pitch up) sequence => from 0210:05 to 0210:50 (45 seconds, during which altitude went from FL350 to FL375).

b) PF was flying by sidestick, but recieved from the start all the relevant PFD flags about his airspeed/flight law situation (he was not blind flying).

c) THS did nothing during this sequence, if adjusted, it would be by tenths of degree, not 10° (this happened during the stall sequence, much later).

d) PF was certainly fully busy at flying the aircraft : his roll (over)correction seems to have induced an oscillation which lasted until the top by rolling right and left, up to 10-12 degrees (left-right); there was at least a pitch up order, then later, insufficient ND orders to correct the pitch angle and climb trajectory (it continued until FL380).

e) I don't know more about respective actions taken by PF and PNF.

airtren It means I better understand what you were telling me about how you experienced the altitude change. :\

That would be my assessment.
Typically, when you undertake a climb, you change both power and attitude. (Or is that now taught differently? It's how I used to teach a climb ...)

Caveat: some have suggested that the PF thought he had an overspeed, based on display anomalies, so perhaps he thought to trade airspeed for altitude. Hard to say.

I don't think a type rated pilot at that altitude would (given the small window of suitable speeds) purposefully bleed off his airspeed to climb 3000 feet. I am of the opinion that a rated pilot would do as pilots are trained to do from day one: he'd use power and pitch attitude to perform a climb. Note, he'd been intending to climb earlier, as evidenced by their discussing why they could not climb yet due the temperatures not being suitable for an altitude change.

So yes, airtren, I am of the opinion that he climbed unintentionally. Granted, if his gauges showed a high airspeed, and an altitude less than FL 350, assigned altitude, you could argue that a stick only altitude correction (and airspeed correction) would be the response. (But wait, if you are in bumpy/turbulent air, you usually hold an attitude, you don't chase airspeed, nor altitude.)

Back to my old question: what did he see?
JD Or, left wing up, nose up, is a correction to a right wing down, nose low, attitude. Whence that attidude? Not sure, but I find A33zab's post of interest.
A33zab
With the above in mind, is there a good reason to believe that AF 447 experienced a g load > 2g? (Does this take us to intermittent and substantial updrafts and down drafts? They did expect to hit some turbulence,)

To follow that thought, are you suggeting a possible malfunction or degradation of the MLA function you spelled out? :confused:
(Hence, PF having to correct a roll in Alt Law ...)

If this happened, might it have left no audit trail in ACARS or FDR?

you calculate with stopped turbines, (correct, a stone need a start speed of vertical 134 m/s to reach a delta-high of 914m against gravity...... he need 13,6 sec.)

but with decreasing speed during climb no longer every energie of the turbines is required against air drag, so they provide more energie into the kinetic system....

In case anyone missed 3holelover's question
Q for Pilots:
Well, if I believed my attitude indicator ...

If my nose attitude was nose low, I'd believe diving.
If my nose attitude was nose up, I'd believe stalled.

If I didn't believe my attitude indicator, you ask a very good question, and I am not sure what my reaction would be.

Your question doesn't include any reference to my primary scan instrument.

Was that intentional? :confused:
By the way, what's my back up Attitude indicator showing?

What is my copilot's attitude indicator showing?
I'd sure as hell ask him.

A few threads back, I discussed the problems of a spin on instruments. Not easy.

This scenario looks equally difficult.

Go back to the first thread on this crash.
One of the common answers provided then was "fly pitch and power"

beside the missing ATC clearance to deviat.... if you follow the plan and do the climb from F350 to F370, with how much pitch would you normal do the climb?



and at what place behind SALPU did they start their climb?
http://cimss.ssec.wisc.edu/goes/blog..._zoom_anim.gif

Takata

Thank you for making clear to me the lack of movement of the THS in this, the initial phase.

I made no suggestion about " blind flying" but I assumed that some at least of the relevant flags on the PDF about the relevant airspeed law situation had not appeared much prior to the pitch-up.

( An earlier generation accident report to a very different aircraft, had pointed out that a good ILS procedure had been done but with the ILS switched off... That was why they had had the accident. The pilot had been so used to seeing the OFF flag that, for him, it was "normal".)

Thanks Lonewolf.

Yes. Partly because we don't know what he saw, and partly because his actions (the one's we've been told about so far) lend credence to the notion he either had no attitude display, or he may not have believed what he saw... and the only tidbits of conversation we know of express doubt: "we have no indications", "je ne comprend rien".

So if that primary display is either absent or doubted, there's my question. -if he did indeed see 40-60 degrees nose up, it would appear from his actions that he wasn't buying that. - and I can well imagine he was looking at a number of rather confusing things - including flagged or absent displays - that could have caused doubt...

Having only had ab-initio instrument flight training myself, I am aware, at least, that one needs to disregard what one "feels" the a/c is doing, and trust your instruments.... But when your confidence in those instruments has been shattered, I can see someone resorting to actions based on what their body tells them.
So, I wonder what most pilots would conclude from that feeling?

Hopefully the CVR will enlighten us as to any further talk of their displays...?

Vague Verbiage
 

The BEA reports on 447 remind me of the US Constitution. The Constitution is sufficiently vague that we have a Supreme Court that continues to interpret its meaning 222 years later.

23% is actually mentioned on P18 in the first interim report.
To be honest, I didn’t do any math, just practical observation. Maybe our BEA Experts will comment on how their estimated CG was that far …


Hopefully guys on the flight decks are discussing the event, but on the procedure side, nothing has changed. The very same confused UAS procedure remains … and remains ...

Where do you get that certainty of a triple ADR fault from ?
To the contrary, Low and High Speed Stabilities may well have been available.


Conclusions, whatever they are, whenever they come, belong to the BEA, but thinking has to belong to everyone.
Right now, the real ones to suffer are the victim's families , and especially the pilot's families, thanks to the last BEA note ...
Forget about the public, forget about us, we're not suffering we're just technically captivated, victim's families are ... and it appears they are also the ones to request the data.

That, and the call for the Captain to return to the cockpit. That's an SOS call, as I see it.

If I am IMC, and I don't believe any of my instruments, the thought that comes to mind is "I am well and truly :mad: ed." I then try to make small control movements to get something to move, or change, that makes more sense than what I am seeing, or not seeing, at the moment, and I try to figure out "how do I get to VFR conditions, and how soon can I do that?"
Try anything that might work, as what's going on now isn't working?
Task the PNF to:
Reset a few circuit breakers to get something to work again?
Cycle some switches on and off so that an instrument may work again.
What I need is:
Attitude reference
Altitude reference
Power reference
Airspeed (but I can work around that if I can get an attitude reference)
VSI
Turn and Slip

Give me what you can, PNF, that's why you are there.

But of course, maybe before we start turning things on and off ...

If your instruments are working, you take the controls, and I'll back you up.

That may be what finally happened somewhere near 10,000 feet on a dark and stormy night. :(

Not wanting to nitpick, just for the sake of correctness, it has to be noted that the 275kts and 215kts were IAS.
For any kind of energy calculation you have to take TAS.
In this case that would be approx. 495kts and 390kts, repectively.

Edit:
This corresponds to ~4200ft but is still very well explicable by the increased drag of the maneuvers. So I don't contradict the statement that the kinetic energy figures are plausible.

Hello 3holelover;

Didn't mean to ignore your question! I sometimes struggle with hypotheticals because I wasn't there.

That acknowledged...

I think Lonewolf_50's last line says it all - fly pitch and power.

That is the drill for a UAS abnormal and that is what will keep the airplane stable while the problem gets sorted out. I think that every other response will likely destabilize the aircraft and make things much more difficult to recover from.

To your question regarding "what would one do?", faced with the losses you mention, I don't for one second pretend to know because I've never been faced with the problem. So hypothetically from my armchair, obviously given the views I have expressed in the past I would do nothing except maintain pitch and power and call for the UAS checklist. The memorized portion of the UAS drill requires that one "level off and troubleshoot" and "doing nothing" (except maintaining control) is being done.

If I began feeling "light in the seat" I would ask what other crew members were feeling while checking the aircraft attitude on the displays I had and try to maintain level flight. Reading the standby in turbulence is a real challenge by the way - the thickness of the little airplane symbol (on the steam instruments) is about 2deg of pitch...a lot when one needs to fine-tune pitch! The job of maintaining stable flight is challenging in turbulence anyway but it must be done.

For the following discussion, we need to understand the layout of the A330 cockpit to see where the following panels are. Here is a rough diagram:


http://www.smugmug.com/photos/i-FXRL...-FXRLjPR-L.jpg


In terms of available attitude information, if the artificial horizons (all 3) are failed it means that IRUs 1 and 2 have failed so, (if I had the presence of mind...again, from the comfort of my armchair), I would ask the PNF to switch the source of the attitude information to the #3 IRU, (ATT HDG, Capt or F/O ON 3), (see diagram below).

It would be unlikely that all 3 IRUs would fail, and there are no ACARS messages that indicate any IRU failures.




http://www.smugmug.com/photos/i-ZZdf...-ZZdf7Db-L.jpg



But let us continue the hypothetical case.

If a PFD display had failed, (mine), I would transfer control to the PNF if he had an attitude display that agreed with the Standby and call out pitch and bank information to help him maintain level flight while we got the QRH out for pitch-power settings.

I would leave the ECAM messages alone until control was assured and stable flight established - which means, when the QRH UAS drill and checklist are completed.

In the A330, one can switch data sources to another DMC (Display Monitor Computer - see schematic below).

So, if one, two or all of the IRUs were working but one's own DMC had failed, one can switch DMCs using the EFIS DMC Control Panel to select either the opposite side display or the #3 display.

One can even toggle one's own PFD information so that the PFD and ND exchange displays in case one's own actual CRT display has failed.

Again, it is unlikely that all 3 DMCs would fail. Here is the DMC switching panels which are located on the far left and right ends of the glareshield. the top knob has 3 selections: "NORM" for one's own DMC, #1 or #2 for the opposite side DMC, and #3 for the backup DMC.




http://www.smugmug.com/photos/i-CMgB...-CMgBstQ-M.jpg




In brief, for all attitude information to have been lost to the crew, all 3 IRUs would have to have failed, or all 3 DMCs would have to have failed or all 4 screens would have to have failed (PFD & ND information cannot be displayed on the ECAM and SD displays). To see how all this fits together, here is a schematic of the entire EFIS control and display system:




http://www.smugmug.com/photos/i-qhQg...-qhQgWwf-L.jpg


Once the attitude information had been regained, maintaining wings-level is paramount then maintaining about 2.5deg pitch attitude is next.

After all this trying, if one still doesn't have attitude information, it is a very bad day and very likely a loss of control, probably a spiral dive, would follow. I think it is reasonable to say that one cannot maintain level cruise flight in an airliner solely by the seat-of-the-pants.

I say a spiral dive and not a stall because maintaining wings completely level without any attitude information (external or internal) is far more challenging in the short term, than maintaining a level pitch attitude. A small amount of bank will start a turn, and also cause the nose to drop and the spiral begins, and quickly develops and tightens because the A330 is so clean and "slippery".

Even in general aviation it is well understood that if a pilot with little or no instrument training loses visual reference with the horizon a spiral dive is the most common outcome. The most well-known event of this kind was John Kennedy Jr's accident some years ago. That was the reason for the introduction decades ago of the requirement for some instrument instruction even at the private pilot level. So loss of attitude information without visual reference to a horizon almost guarantees loss-of-control of some kind, whether a high-speed spiral dive (very likely) or a stall, (less likely, for reasons given).

The BEA Update doesn't state that the #2 PFD attitude information is not recorded. However, the Update does clearly provide information on the bank and pitch attitudes throughout the report and this information had to come from somewhere. I think it is reasonable to assume that if the data was available on the SSFDR, for the reasons given above regarding failures of redundant systems, it was displayed on one/both PFD(s) and ISIS. There are no ACARS messages indicating failures which would prevent such display.

I think to claim that the pitch-up was the result of the PF reacting to a display that was different than the PNFs or the ISIS is not reasonable for two reasons: a) system redundancy and absence of failure messages, and b) the PNF would either have the same "wrong" display or would react and call out his own display showing something different. Also, at what time would such a failure have occurred? There is no connection between the pitot failures and a failures of attitude displays.

I fully realize that I am inferring a great deal here but I am also trying to think about your hypothetical scenario logically. If we are to think hypothetically, at least the hypothesis must be internally consistent - we can't just say this and that is "possible" without accounting for the design of the aircraft and its systems which preclude some scenarios.

I'm completely open to alternate explanations of the pitch-up but the explanations have to make sense and withstand reasonable objections.

At some point there has to be a rational explanation that makes "if-then" connections, ideally all the way back to the originating event at 02:10:05 even if some of those connections may be tenuous.

I know that isn't possible at the moment because we all have the same bit of information from the BEA Update. But some things may be inferred, (admittedly, some more "loosely" inferred than others).

I'm not stuck on the notion that the initial aft-movement of a sidestick was intentional. But at some point, first the initial pitch-up, then the continuing aft-backstick must both be explained.

I hope this is of some use 3holelover...as I say, it's all armchair work but those guys had to do it for real. As I have said many times, discussing crew actions is not "blaming the crew". In investigative work there are no "off-limits" areas however, and that can come across as "blaming". For reasons we're all familiar with, that unfortunately seems to be a way our culture thinks about these things.

Lonewolf_50;
Yes, exactly. Although there are no circuit breakers that would accomplish this purpose in the cockpit, (the FMGEC cb's are on the overhead but they wouldn't help), the switching capabilities that I discuss above would be of immense help in any attitude failures, so long as there is attitude information available from an IRU.

Hmm, I'm afraid you've got a little quirk in your calc.

Energy loss is 1/2 (V1^2 - v2^2) which is quite a different thing from 1/2 (v1 - v2)^2.

You might want to recalculate with the adapted formula and will then come to the conclusion which has been accepted here that the energy transformation matched quite OK.

Hi CONFiture,
Quite simply if, at any point, you've got 3 valid ADRs and a failure makes those 3 ADRs to be rejected by all PRIMs and Autoflight System (AFS)... it will certainly be called a triple ADR fault. That is what happened starting at 0210:05, in all certaincy (this is also stated as a fact from the 1st BEA report).

This relevant fault was: PROBE-PITOT 1X2 / 2X3 / 1X3 (9DA).
Its meaning is quite clear: total pressure was out of boundaries and different at each probe-pitot source (9DA1, 9DA2, 9DA3) and the following consequences are well known on ADRs output channels as well as with other systems (A/FLT, F/CTL, NAV) using those values.

Hence, from this point, ALT2 without valid airspeed/Mach and SPEED LIMIT FLAG on PFD make it quite certain that Low and High Speed Stabilities were NOT available.

Of course, you are right about that (batteries). The above quote sumarizes precisely what I meant by "complete [AC] electrical failure".

henra:
If they are flying in a column of air that was moving somewhere betwen 1-2000 down (a down draft) you might get to about 3000 feet up with your figure there. ;) Just a thought.

@Takata:
 

Quote:

---

Quite simply if, at any point, you've got 3 valid ADRs and a failure makes those 3 ADRs to be rejected by all PRIMs and Autoflight System (AFS)... it will certainly be called a triple ADR fault. That is what happened starting at 0210:05, in all certaincy (this is also stated as a fact from the 1st BEA report).

---

I will disagree with the statement "a failure makes those 3 ADRs to be rejected"
Out of 3 sources FCPC can reject only 1 outlier ADR, but the other 2 remain because FCPC is not able to determine which one or even both are delivering wrong information.
If both keep on delivering different information for more than 10s the NAV ADR DISAGREE message is triggerd. This message was not present @ 02:10:16 or subsequent seconds but ca. 2 minutes later.
The first UAS was only transient, ADR 1 lasted only few seconds, ISIS (ADR 3) was absent for nearly 1 minute.

The NAV IAS DISCREPANCY message, triggered when there is a difference in ADR1 (LH PFD) & ADR 2 (RH PFD) was not present.
ADR 2 therefore must have been (+ or - 30Kts) with ADR 1 at that time and was - like ADR 1 - only absent for few seconds (9s or less).

As said the NAV ADR DISAGREE message is presented because crew has to make a decision to elaborate the ADR in error by switching off this (or multiple ADRs) so it will not be available for the FCPC also.


Same for this failure message, in fact you should read: PROBE-PITOT 1+2 or 2+3 or 1+3 (9DA?).
Meaning there are 2 or more PITOT-PROBES affected but BITE/CMC can't determine which 2 (or more) are faulted.
This fault is indeed correlated with the first UAS event but same message would have been correlated to the second UAS event @ 02:12 however only the first occurance will be recorded en transmitted to CMC/CFR/PFR.

Probe-pitot 1+2/2+3/1+3
 

Hi A33Zab,
Which is also exactly my reading of the fault:
total pressure was out of boundaries [meaning that ADRs polled airspeed value dropped by 30 kts in one second or less] but was different at each probe-pitot source (9DA1, 9DA2, 9DA3)

Then, your explanation is the same than mine : the system can't dertermine which source (pitot-probe) faulted, because all 3 values were at first valid and coherent (condition for triggering this fault and monitoring), then diverged without remaining consistant with each others, hence, there was NOT an ADR DISAGREE message that could be triggered at this point (0210:05). The system was not able to eliminate the outlier ADR during the speed monitoring sequence (DISAGREE condition false: elimination of 1 ADR and other two ADR imputs different). Consequently, all three ADR output would be rejected both at PRIMs (FCPC1 & 2) and AFS level (no matter if one ADR output could have been valid).

Also IAS DISCREPANCY would be triggered if PFD 1 & 2 readings were showing a difference of at least 16 kt during some time. This condition may not have lasted long enough for doing so, hence no ACARS if such fault would be sent (not sure) after consolidation (2-3 seconds). It doesn't mean that this ECAM wasn't displayed at all in the cockpit, but it could have been intermitent during a very short duration. Also, there is nothing in BEA narrative telling us that the crew noticed something before AP disconnected. In many other cases, crews were alerted by experiencing airspeed fluctuations; it seems not to be the case here: it was brutal.

Consequently from those conditions, I'm deducing that ADR2 was also faulty and could have been the very first to drop. This is fully coherent with an environmental fault affecting the same probes, the same way, in a very short time interval.

Your conclusion doesn't match with the data:

In BEA last note :
1) The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS).

2) The inconsistency between the speeds displayed on the left side [ADR1] and on the ISIS [ADR3] lasted a little less than one minute [inconsistency stopped before 0211:05]
From the BEA narrative:
- 0210:05 -> ADR1 followed by ADR3 sharp fall;
- 0211:06 -> ADR1 & ADR3 speeds coherent and "valid" again => 1 minute error;
- 0211:40+ few seconds -> all of the recorded speeds became invalid again (1). Note 1: When the measured speeds are below 60 kt, the measured angle of attack values are considered invalid and are not taken into account by the systems. When they are below 30 kt, the speed values themselves are considered invalid.

Consequently, the ADR DISAGREE message triggered (0212 => 0211:40+) is due to this second (or later) speed/alpha issues with ADRs, at which time conditions were different as 1 ADR would have been rejected at FCPCs level.

Your above conclusion doesn't match also with the first BEA report (see p.54-55) about this fault explanation:
"The presence of the F/CTL RUD TRV LIM FAULT message indicates that EFCS monitoring had been activated and that the alternate law had been maintained."
Hence, it was already obvious from all the systems declared INOP that the first probe fault was NOT transient and it was confirmed by the DFDR showing that the inconsistency lasted about 1 minute on both ADR1 & ADR3 (more than enough for a triple ADR fault condition).

You should also keep in mind that this sequence is not from a PFR (Post Flight Report) but a CFR/ACARS, hence, everything is not sent by this mean (e.g. no cockpit Stall, overspeed warnings). Failures are labelled following their logical compilation order and could have covered various system messages having the same ATA header => 341.

You may want to list every ATA 341 fault at FCPC and AFS level and see what they could have been during this 1 mn correlation window opened.

Also, AIRBUS acknowledged this PROBE-PITOT fault as being possibly part of an UAS signature, even if not the more frequent:

The TBS (see below) mention about this fault "Disagree of the Pitot Probe Data in the FCPCs" that if the fault was transient, F/CTL ALTN LAW, would have been displayed only few seconds in the cockpit (then return to NORMAL, while an acknowledgement from the crew is also stamped 0210:16)- Beside, there would be no subsequent ECAM warnings and flags on PFDs.

A gracious good morning, takata.

Thank you for such specific and important data.

You mention that BEA do not state any "recognition" (by pilots) of noticeable a/s problems prior to a/p loss. You also mention that many prior cases of UAS did have such recognition by pilots. You call it 'brutal'. Can you explain?

It underscores the suddenness of the auto loss to the crew. I cannot recall a discussion of events probable at a/p drop before. Your fine tuning of the FCS' reactions and mitigations are enlightening.

@3holelover
I do believe you have just proven one of Bear's previous points. :hmm:


Perhaps what you meant to say that the PF/PNF were put into cognitive overload by the system failures, sequence of error messages, failed indications and aircraft behaviors and changes of laws.

You might do well to read the seminal paper by Reason on the swiss cheese model of error propagation. There plenty of slices of holey cheese to pass around in most aircraft accidents and incidents.


(Google "Reason Swiss Cheese Model" there are lots of hits to read)

Edit:
As an example read the prescient introductory paras in this wiki entry - Organizational models of accidents - Wikipedia, the free encyclopedia

Is this your reference? -
BEA Interim #2, 1.16.3 Study of losses of or temporary anomalies in indicated speeds:

Hi Bearfoil,
In many UAS events, (but not all), the attention of pilots was at first attracted by either airspeed fluctuations on PFDs, either autothrust changes before autopilot disconnected. In one case, it is mentioned that CAS made several yo-yos on both PFDs. In those recorded cases with fluctuations, this NAV IAS DISCREPANCY message would tilt on ECAM. It means that airspeeds displayed on each PFDs are outside a certain range, which is constantly monitored by the system, while certified instrument possible variations at cruise, depending on source, altitude and speed are below Mach 0.009 (=3-4 kt above FL350).

In fact, I noticed an incoherence about this NAV_ADR_DISAGREE message: In the documentation, like A33Zab mentioned it above, it is stated that in case of 2 or 3 ADR fault, this ECAM would be displayed, while I believe this is only true in the first case (2 ADRs) because it is contradictory with NAV_ADR_DISAGREE condition which needs first an ADR to be rejected by the PRIMs (this rejection of the "outlier" is discrete). Hence, in case of triple ADR fault happening in a very short time, without a single ADR drifting earlier from the other two, this condition won't be true.

Our case signature of this first ADR fault (0210) is a triple one. Beside, it is much more logical with the Probe-Pitot fault which is also a triple one, the system being unable to determine which one of the three has faulted. How could the system "eliminate" the first ADR by itself?

Hence, this is why I'm saying it was brutal as there was a fast ice build-up, a sharp speed drop, without erratic speed readings, affecting all the probes in few seconds that caught the crew by surprise. No warnings due to autothrottle behavior or IAS DISCREPANCY tilting on ECAM display.

But please, Bear, don't rebounce on my posting in order to advance your usual "structural" failures fantastic theories, as this was a genuine ADR fault due to severe probe icing in all certaincy.

Their huge problem was that when the first ADR fault self-cleared at 0211, a second followed at 0211:40 (invalid parameters), then possibly a third one at 0212 (ADR DISAGREE)...

Hi HN39,
See the Expertise Judicial report link I posted few pages back. (here it is: rapport d'expertise Rio-Paris)

Not really fantastic, at least in the case of 'superbe', no?

At last I believe I am tracking you, and surprised at how much we agree.
That three probes would block simultaneously, in rate as well as time frame, seems fantastic to me. How quickly does a/p respond to declining a/s's, and for how long is it "allowed" to? I am starting to suss the Law, so thanks to you, I have some actual data to consider, phrased in language I get.

What is monitored is CAS value, by two independant systems working in parallel: actually -> 0.45 second at autoflight level (1) and 1 second at FCPC level (2).
1) Fluctuation fo CAS resulting of 20 kt change in 0.45 seconds will cause A/P to disconnect, and further A/FLT systems if confirmed.
2) Fluctuation of CAS resulting of 30 kt change in 1 second will cause ALTERNATE LAW 2 to trigger, and further F/CTL if confirmed.

The next step is a 10 seconds monitoring test which retains the last valid CAS (median value of 3 ADRs) for comparison with CAS value at the end of this time window.

Ahhh.... So the a/c flies for ten seconds on one read? Is that the ten second interval I suss @ 2:10:16 "so.....we've lost the speeds, Alternate Law?" (PNF?).

Am I close? If the a/c was ten seconds into flight calculated on one airspeed, what could the PF/PNF be seeing when the reads update?

Do they? Is PITCH and POWER any more difficult to acquire if the a/c has degraded in assiete, during "monitoring"?

thanks takata :ok:

NO again, you are far!
Autopilot disengages and ALT2 is triggered immediately without waiting for 10 seconds confirmation.
CAS_System is used by aircraft avionics systems (autoflight, flight controls); it is NOT displayed on PFDs.
* Captain's PFD: CAS1 = ADR1 = real value displayed if > 30 kt.
* F/O's PFD: CAS2 = ADR2 = real value displayed if > 30 kt.
* Standby: CAS3 = ADR3 (not displayed, in replacement for CAS1 or 2)
* ISIS: CAS3bis = same probes as ADR3, but analogical values (no ADMs computation) = real value displayed if > 30 kt.

Consequently, if Captain's Probe-Pitot becomes clogged and ADR1 airspeed drops immediately from 275 kt to 60 kt, Captain's PFD will actually display 60 kt even if the system CAS will retain the last valid value of 275 kt for monitoring all ADRs output during 10 seconds following the fall of ADR1. Same for F/O, ISIS with their respective ADRs.
That's how RTLU would retain the last valid airspeed if the 10 seconds airspeed test failed but, if the test is passed, it will function normally.

bearfoil, the definitions of conspiracy follow:

conspiracy (plural conspiracies)

1. The act of two or more persons, called conspirators, working secretly to obtain some goal, usually understood with negative connotations.
2. (law) An agreement between two or more persons to break the law at some time in the future.
3. A group of ravens.

Now, in the sense of the second definition do you believe there is a conspiracy involved in BEA?

I also personally wonder if you are still insisting things fell off the plane or quit working without any evidence in the ACARS messages, do you?

More like, could a lack of response to an initial smaller NU response have led to continued NU application until the sudden response happened. They were in turblence, or chaotically moving air. Suppose that air movement was enough to momentarily negate the response of the aircraft to the pitch change. That might have altered the PF's response.

So he rather rapidly climbed and then reduced the climb rate. Pitots cleared. At least PNF got airspeed and both received a stall warning. And it all balled up at that moment with the PF response.

As an aside I'll be interested when the report comes out of PNF was kept abreast of what PF was doing as he did it, "I'm climbing for a little more altitude to (whatever)." If such statements as he was acting were not made that suggests to me a potential cultural problem for the team environment in the cockpit.

Lonewolf_50, re A33zab's remarks note the bit about speed > 250 kts.
With speed lost could MLA function at all?

That is why my initial calculation was based on zero speed with a delta. I used the fact that the plane was in a stable state with respect to power and drag. Then I calculated an energy tradeoff for the change in altitude. Admittedly this is at best a first approximation. Nonetheless, that was not accepted around here. Either calculation has a reasonable chance as a first approximation to what happened. The plane was in heavy turbulence moving through chaotic winds.

Above I mentioned it may have received stick up in response to a down draft, the plane then moving into a strong updraft and surprised PF. The chaotic winds they were going through may preclude a really accurate assessment of the energy tradeoff. It is suspicious that the number comes out so close to what was apparently observed.